1. Field of the Invention
This invention relates to a magneto-optical recording and/or reproducing apparatus for use, for example, in an external storage of a computer or an information recording and/or reproducing apparatus for recording and/or reproducing information such as audio or video signals or the like.
2. Description of the Prior Art
With recent developmental progresses in electronic computation and high speed transmission of a large volume of information, nonvolatile storage having a low cost, high storage density and capacity and high transmission speed has been required. In order to meet these requirements, the magnetic disc apparatus has been widely used. However, problems such as low recording density and high price per information unit have been associated with such apparatus. Further, the reliability is low in the case of the magnetic disc apparatus whose recording medium is exchangeable. Optical recording technology has come into a limelight as a technology capable of solving these problems, particularly, rewritable magneto-optical recording technology is now being observed with a great expectation by many industries.
In the magneto-optical recording technology, it is difficult to carry out over-write by means of the recording procedure based on optical modulation and as a result, an over-write method based on magnetic modulation is under consideration recently. Many reports on this are available. This method resembles the fixed magnetic disc recording method, and the magnetic field to be applied to a magneto-optical disc is modulated by a lift-type magnetic head, and the size of recording bit is controlled by the diameter of a converged laser beam.
In a magneto-optical recording and/or reproducing apparatus, magneto-optical disc as a recording medium is generally exchangeable and contained in a cartridge. When a magneto-optical disc is to be removed from the apparatus for replacement, it is required to be lifted up from the spindle motor and removed from the turntable on which it is mounted. In this case, the magnetic head is required to be lifted up in a direction to be apart from the magneto optical disc. Also, the magnetic head is required to be further lifted up in order to prevent it from colliding with the disc cartridge.
In the conventional exchangeable magnetic disc apparatus, the lifting and lowering of the magnetic head for exchanging a recording medium were carried out by deforming a loadbeam, which is well-known as a load means, for urging the magnetic head to the magnetic disc. However, in the magneto-optical recording and/or reproducing apparatus, the magnetic head is required to be evaded as explained above including the cartridge, so that the magnetic head is required to be moved vertically by as much as several milli-meters for this purpose. As a result, the conventional method of vertically moving the magnetic head by deforming the loadbeam in order to avoid collision with the cartridge can cause the loadbeam spring to exceed its allowable stress, resulting in either permanent strain residual or fatigue fracture. In addition, if the loadbeam is designed sufficiently conservatively and an allowable strain is introduced, traceability of the magnetic head to a magneto-optical disc will be decreased. This tends to cause an accident such as, for example, a crush, resulting in the destruction of data.